'Grape gatherers' in the Bible

“If grape gatherers came to you,Would they not leave gleanings?If thieves came by night,They would destroy only until they had enough.

“If thieves came to you,If robbers by night—O how you will be ruined!—Would they not steal only until they had enough?If grape gatherers came to you,Would they not leave some gleanings?

Woe is me! For I amLike the fruit pickers, like the grape gatherers.There is not a cluster of grapes to eat,Or a first-ripe fig which I crave.